package test;

import java.util.Stack;

public class Demo1 {
    public boolean isValid(String s) {
        Stack<Character>stack = new Stack<>();
        for (int i = 0; i < s.length(); i++) {
            char ch = s.charAt(i);
            if (ch == '{' || ch == '[' || ch == '('){
                stack.push(ch);
            }else {
                if (stack.isEmpty()){
                    return false;
                }
                if (stack.pop() == '(' && ch != ')'){
                    return false;
                }
                if (stack.pop() == '[' && ch != ']'){
                    return false;
                }
                if (stack.pop() == '{' && ch != '}'){
                    return false;
                }
            }
        }
        return stack.isEmpty();
    }
}
